1. Field of the Invention
This invention relates to a rotary printer. More specifically, this invention relates to a printer of labels having large characters for packing cases or the like.
2. Description of the Prior Art
In a label printing unit such as, for example, disclosed in U.S. Pat. No. 3,951,061, issued Apr. 20, 1976, a plurality of adjacent print wheels carrying peripherally mounted printing facets are intermittantly rotated by a stepping motor until the desired facet is in printing position. When an individual facet is in the appropriate printing position, one of a number of hammers is actuated to strike the label to be printed to force the label and an inked tape into contact with the facet. Subsequently, the printing wheels are driven in continued intermittant fashion with other hammers being selectively actuated until the label has been printed, at which point the label is removed and a new label inserted into the printing position. U.S. Pat. No. 3,973,488, issued Aug. 10, 1976 also discloses a label printing device which causes printing wheels to be intermittantly rotated. In this case, however, the printing wheel itself acts as the hammer and is moved in a manner which brings its facet into contact with an inked tape and the label to be printed.
These and similar prior devices are extremely complicated devices requiring many precisely synchronized intricate moving parts. As such, they are expensive to manufacture and are subject to operation difficulties brought about through wear of the multiple parts. In addition, each of these devices operates in a manner in which the label is repeatedly struck at different times in different places until all of the desired information is printed. This mode of operation creates the possibility of movement of the label resulting in blurred or out of line characters or in two characters being superimposed. It is desirable therefore to have a printing device which aligns all of the character printing facets and prints all of the characters at one time. It is also desirable to provide a label printing device which is relatively simple in operation, which has few intricate moving parts, and which dispenses with such expensive parts as accurate stepping motors. It is still further desirable to provide a label printing device which may readily be scaled up in size in order to obtain a large label printing device for warehouse crates, for example, without incurring undue expense.